Actually I would watch the original 3 first. Then the remade original 3 and then episodes 1 through 3. Maybe take a month off between each trilogy to get the feel (sort of) for what everyone else waited for and anticipated between releases. That in my opinion is why Lucas was so successful the story left you with wanting more. Except in the case of Jar jar Binks but I won't go there! And yes I hope Disney and HF do a bang up job on the finally!

4 (get them used to the older look and feel)
1 (for stark contrast, also acts as "flashback" to Luke's father's days)
2 (for the first mild hints of Vader possibly being Annakin)
5 (for the big "reveal", but this time, you have a bit of foreshadowing)
3 (see how he got the way he did)
6 (to wash the bitter taste of #3, and for the conclusion of the redemption story)

If you feel like it, you could even include one or both of the Star Wars "Clone Wars" animated series right before watching #3.

P.S. The Disney new trilogy will most likely happen in one of (or a new one inside) the expanded universe settings, where Han is married to and has children with Leia, so having Han Solo play the grizzled old dad who used to be a dashing rogue would make sense.
Oh, and I understand that all "main 3" of the original trilogy (Han, Leia, Luke) might make an "old self" appearance in the new trilogy. But I expect their CHILDREN to be the main focus of the soon-to-be trilogy anyway, so their presence is a mix between cameo and plot setting.

Sickone summed it up the way I would have chronologically in this instance. Even the original animated series would explain a lot out and fill in some gaps. However if you wanted the entire true experience go to a book store(online ones are your best bet) and buy the entire series. It will be a TON of books by the way. :-)

rofl @ the "wash the bitter taste of 3 out of their mouths"... god that movie was awful.

Anyway I like that order for plot line purposes, makes for a nice over all understanding of the original trilogy by filling in some of the backstory that the second trilogy (however bad it was) brought to the table.